raidreconf(8)						      System Manager's Manual						     raidreconf(8)

NAME

       raidreconf - reconfigure RAID arrays

SYNOPSIS

       raidreconf -h {--help}

       - or -

       raidreconf -V {--version}

       - or -

       raidreconf -o oldraidtab -n newraidtab -m /dev/md?

       - or -

       raidreconf -i /dev/sd?? -n newraidtab -m /dev/md?

       - or -

       raidreconf -n newraidtab -m /dev/md? -e /dev/sd??

WARNING

       You should back up all data BEFORE any attempt is made to reconfigure a RAID device.  YOU HAVE BEEN WARNED.

       The  author  will give you no guarantee whatsoever, that this program works in any specific way at all. It may well destroy all data on any
       device connected directly, indirectly, or not at all, to any system this software is used on.  Please use this  stuff  with  care,  if  you
       decide to use it at all.

       Ok, that said, let's see how to actually use it	:-)

DESCRIPTION

       raidreconf will read two raidtab files, an old one, and a new one.  It will then re-build your old array to match the configuration for the
       new array, while retaining all data possible.

       It can also be used to import a single block-device into a RAID array (using more block devices), or export a RAID array to a single block-
       device.

       raidreconf can, of course, only retain your original data if you grow the configuration.  If you shrink the configuration from say, P bytes
       to Q bytes, raidreconf will retain the first Q bytes of your original data, but everything from Q bytes to the end of the old array  (to  P
       bytes) will be lost.

       Currently raidreconf can grow and shrink RAID-0 and RAID-5 arrays, and import non-RAID devices into a new RAID-0 or RAID-5.

       The whole purpose of raidreconf is to be able to add disks to an existing array, or convert it to a new type (eg. RAID-0 to RAID-5) without
       losing data. raidreconf will move the existing data around on your array, to match the layout of the new array.

OPTIONS

       -h {--help}
	      Raidreconf will print a short help message, and exit.

       -V {--verbose}
	      Raidreconf will print it's version information, and exit.

       -o {--old} oldraidtab
	      Specifies the path name of the old (current) raidtab.  NOTE: raidreconf performs some tests to ensure that this  configuration  file
	      matches  the  raid  superblocks stored on the disk, but there may be scenarios where the two are in conflict, but aren't detected as
	      such.  Be very careful to specify this file properly.

       -n {--new} newraidtab
	      Specifies the path name of the new raidtab.  After  raidreconf  finishes,  copy  the  newraidtab	to  the  oldraidtab  location,	as
	      raidreconf doesn't perform this (potentially dangerous) operation.

       -m {--mddev} /dev/md?
	      Specifies the name of the raid array to modify.

       -i {--import} /dev/sd??
	      Specifies the name of the device to import from.

       -e {--export} /dev/sd??
	      Specifies the name of the device to export to.

BUGS

       Perhaps	many.  Well, the basic RAID-0 growth, shrink and import algorithms seem to work, but there are lots and lots of consistency checks
       and graceful error handling missing.

       The RAID-5 algorithms are simplistic, with little optimization other than that provided by the buffer layer.  Conversions between non-RAID,
       RAID-0, and RAID-5 all *seem* to work, but there may be some bugs left yet.

       If an error occurs during reconfiguration, a power failure for example, restore from backup (you DID make a backup, right?), and try again.

       Although RAID-4 is not supported, and almost no one uses it, it would be almost trivial to add.

REPORTING BUGS

       Since  this is highly experimental software, there are a number of known bugs already.  The author would of course like to know about bugs,
       but at this stage in development you shouldn't waste too much of your time trying to hunt them down.  They're  probably	known,	and  maybe
       already fixed in the author's tree.

       Report bugs to <bugs@oss.connex.com>. ?????

AUTHOR

       raidreconf was written in 1999 by Jakob Oestergaard <jakob@ostenfeld.dk>

       The RAID-5 routines were written by Daniel S. Cox in 2001 <dcox@connex.com>

SEE ALSO

       mkraid(8), raidtab(5), raidstart(8), raidhotadd(8), raidhotremove(8), raidstop(8)

																     raidreconf(8)